| 1 | ******************************************************* |
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| 2 | * * |
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| 3 | subroutine nucleaCO2(pco2,temp,sat,n_ccn,nucrate, |
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| 4 | & n_ccn_h2oice,rad_h2oice,nucrate_h2oice, |
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| 5 | & vo2co2) |
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| 6 | USE comcstfi_h |
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| 7 | |
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| 8 | implicit none |
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| 9 | * * |
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| 10 | * This subroutine computes the nucleation rate * |
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| 11 | * as given in Pruppacher & Klett (1978) in the * |
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| 12 | * case of water ice forming on a solid substrate. * |
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| 13 | * Definition refined by Keese (jgr,1989) * |
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| 14 | * Authors: F. Montmessin * |
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| 15 | * Adapted for the LMD/GCM by J.-B. Madeleine * |
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| 16 | * (October 2011) * |
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| 17 | * Optimisation by A. Spiga (February 2012) * |
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| 18 | ******************************************************* |
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| 19 | ! nucrate = output |
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| 20 | ! nucrate_h2o en sortie aussi : |
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| 21 | !nucleation sur dust et h2o separement ici |
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| 22 | !#include "tracer.h" |
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| 23 | #include "microphys.h" |
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| 24 | c#include "microphysCO2.h" |
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| 25 | |
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| 26 | c Inputs |
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| 27 | DOUBLE PRECISION pco2,sat,vo2co2 |
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| 28 | DOUBLE PRECISION n_ccn(nbinco2_cld), n_ccn_h2oice(nbinco2_cld) |
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| 29 | REAL temp |
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| 30 | |
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| 31 | c Output |
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| 32 | ! DOUBLE PRECISION nucrate(nbinco2_cld) |
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| 33 | DOUBLE PRECISION nucrate(nbinco2_cld) |
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| 34 | DOUBLE PRECISION nucrate_h2oice(nbinco2_cld) ! h2o as substrate |
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| 35 | |
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| 36 | double precision rad_h2oice(nbinco2_cld) ! h2o ice grid (as substrate) |
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| 37 | |
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| 38 | c Local variables |
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| 39 | DOUBLE PRECISION nco2 |
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| 40 | c DOUBLE PRECISION sigco2 ! Water-ice/air surface tension (N.m) |
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| 41 | c external sigco2 |
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| 42 | DOUBLE PRECISION rstar ! Radius of the critical germ (m) |
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| 43 | DOUBLE PRECISION gstar ! # of molecules forming a critical embryo |
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| 44 | DOUBLE PRECISION fistar ! Activation energy required to form a critical embryo (J) |
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| 45 | ! DOUBLE PRECISION zeldov ! Zeldovitch factor (no dim) |
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| 46 | DOUBLE PRECISION fshapeco2 ! function defined at the end of the file |
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| 47 | DOUBLE PRECISION deltaf |
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| 48 | |
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| 49 | c Ratio rstar/radius of the nucleating dust particle |
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| 50 | c double precision xratio |
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| 51 | |
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| 52 | double precision mtetalocal,mtetalocalh ! local mteta in double precision |
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| 53 | |
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| 54 | double precision fshapeco2simple,zefshapeco2 |
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| 55 | |
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| 56 | |
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| 57 | integer i |
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| 58 | |
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| 59 | LOGICAL firstcall |
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| 60 | DATA firstcall/.true./ |
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| 61 | SAVE firstcall |
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| 62 | |
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| 63 | c ************************************************* |
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| 64 | |
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| 65 | mtetalocal = dble(mtetaco2) !! use mtetalocal for better performance |
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| 66 | mtetalocalh=dble(mteta) |
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| 67 | |
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| 68 | |
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| 69 | if (sat .gt. 1.) then ! minimum condition to activate nucleation |
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| 70 | |
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| 71 | nco2 = pco2 / kbz / temp |
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| 72 | rstar = 2. * sigco2 * vo2co2 / (kbz*temp*dlog(sat)) |
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| 73 | gstar = 4. * pi * (rstar * rstar * rstar) / (3.*vo2co2) |
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| 74 | |
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| 75 | fshapeco2simple = (2.+mtetalocal)*(1.-mtetalocal)*(1.-mtetalocal) |
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| 76 | & / 4. |
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| 77 | |
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| 78 | c Loop over size bins |
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| 79 | do 200 i=1,nbinco2_cld |
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| 80 | c write(*,*) "IN NUCLEA, i, RAD_CLDCO2(i) = ",i, rad_cldco2(i), |
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| 81 | c & n_ccn(i) |
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| 82 | |
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| 83 | if ( n_ccn(i) .lt. 1e-10 ) then |
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| 84 | c no dust, no need to compute nucleation! |
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| 85 | nucrate(i)=0. |
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| 86 | goto 210 |
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| 87 | endif |
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| 88 | |
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| 89 | if (rad_cldco2(i).gt.3000.*rstar) then |
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| 90 | zefshapeco2 = fshapeco2simple |
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| 91 | else |
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| 92 | zefshapeco2 = fshapeco2(mtetalocal,rad_cldco2(i)/rstar) |
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| 93 | endif |
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| 94 | |
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| 95 | fistar = (4./3.*pi) * sigco2 * (rstar * rstar) * |
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| 96 | & zefshapeco2 |
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| 97 | deltaf = (2.*desorpco2-surfdifco2-fistar)/ |
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| 98 | & (kbz*temp) |
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| 99 | deltaf = min( max(deltaf, -100.d0), 100.d0) |
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| 100 | |
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| 101 | if (deltaf.eq.-100.) then |
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| 102 | nucrate(i) = 0. |
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| 103 | else |
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| 104 | nucrate(i)= dble(sqrt ( fistar / |
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| 105 | & (3.*pi*kbz*temp*(gstar*gstar)) ) |
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| 106 | & * kbz * temp * rstar |
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| 107 | & * rstar * 4. * pi |
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| 108 | & * ( nco2*rad_cldco2(i) ) |
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| 109 | & * ( nco2*rad_cldco2(i) ) |
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| 110 | & / ( zefshapeco2 * nusco2 * m0co2 ) |
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| 111 | & * dexp (deltaf)) |
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| 112 | |
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| 113 | |
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| 114 | endif |
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| 115 | |
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| 116 | 210 continue |
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| 117 | |
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| 118 | if ( n_ccn_h2oice(i) .lt. 1e-10 ) then |
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| 119 | c no dust, no need to compute nucleation! |
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| 120 | nucrate_h2oice(i)=0. |
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| 121 | goto 200 |
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| 122 | endif |
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| 123 | |
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| 124 | if (rad_h2oice(i).gt.3000.*rstar) then |
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| 125 | zefshapeco2 = (2.+mtetalocalh)*(1.-mtetalocalh)* |
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| 126 | & (1.-mtetalocalh) / 4. |
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| 127 | else |
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| 128 | zefshapeco2 = fshapeco2(mtetalocalh,rad_h2oice(i)/rstar) ! same m for dust/h2o ice |
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| 129 | endif |
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| 130 | |
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| 131 | fistar = (4./3.*pi) * sigco2 * (rstar * rstar) * |
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| 132 | & zefshapeco2 |
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| 133 | deltaf = (2.*desorpco2-surfdifco2-fistar)/ |
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| 134 | & (kbz*temp) |
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| 135 | deltaf = min( max(deltaf, -100.d0), 100.d0) |
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| 136 | |
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| 137 | if (deltaf.eq.-100.) then |
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| 138 | nucrate_h2oice(i) = 0. |
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| 139 | else |
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| 140 | nucrate_h2oice(i)= dble(sqrt ( fistar / |
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| 141 | & (3.*pi*kbz*temp*(gstar*gstar)) ) |
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| 142 | & * kbz * temp * rstar |
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| 143 | & * rstar * 4. * pi |
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| 144 | & * ( nco2*rad_h2oice(i) ) |
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| 145 | & * ( nco2*rad_h2oice(i) ) |
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| 146 | & / ( zefshapeco2 * nusco2 * m0co2 ) |
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| 147 | & * dexp (deltaf)) |
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| 148 | endif |
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| 149 | |
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| 150 | |
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| 151 | |
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| 152 | 200 continue |
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| 153 | |
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| 154 | else |
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| 155 | |
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| 156 | do i=1,nbinco2_cld |
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| 157 | nucrate(i) = 0. |
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| 158 | nucrate_h2oice(i) = 0. |
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| 159 | enddo |
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| 160 | |
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| 161 | endif |
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| 162 | |
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| 163 | return |
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| 164 | end |
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| 165 | |
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| 166 | ********************************************************* |
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| 167 | double precision function fshapeco2(cost,rap) |
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| 168 | implicit none |
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| 169 | * function computing the f(m,x) factor * |
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| 170 | * related to energy required to form a critical embryo * |
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| 171 | ********************************************************* |
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| 172 | |
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| 173 | double precision cost,rap |
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| 174 | double precision yeah |
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| 175 | |
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| 176 | !! PHI |
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| 177 | yeah = sqrt( 1. - 2.*cost*rap + rap*rap ) |
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| 178 | !! FSHAPECO2 = TERM A |
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| 179 | fshapeco2 = (1.-cost*rap) / yeah |
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| 180 | fshapeco2 = fshapeco2 * fshapeco2 * fshapeco2 |
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| 181 | fshapeco2 = 1. + fshapeco2 |
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| 182 | !! ... + TERM B |
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| 183 | yeah = (rap-cost)/yeah |
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| 184 | fshapeco2 = fshapeco2 + |
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| 185 | & rap*rap*rap*(2.-3.*yeah+yeah*yeah*yeah) |
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| 186 | !! ... + TERM C |
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| 187 | fshapeco2 = fshapeco2 + 3. * cost * rap * rap * (yeah-1.) |
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| 188 | !! FACTOR 1/2 |
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| 189 | fshapeco2 = 0.5*fshapeco2 |
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| 190 | |
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| 191 | return |
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| 192 | end |
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